1. Field of the Invention
The present invention relates to exchange of the refrigerant in a refrigeration cycle device, in particular, a refrigeration cycle device in which a refrigerant is newly exchanged while newly exchanging only a heat source equipment and an indoor unit without exchanging connection pipes for connecting the heat source equipment to the indoor unit, a method of exchanging the device, and a method of operating the device.
2. Discussion of Background
In FIG. 11, an air conditioner of a separate-type which is generally and conventionally used is shown. In FIG. 11, reference A designates a heat source equipment; numerical reference 1 designates a compressor; numerical reference 2 designates a four-way valve; numerical reference 3 designates a heat exchanger on a heat source equipment side; numerical reference 4 designates a first control valve; numerical reference 7 designates a second control valve; and numerical reference 8 designates an accumulator, wherein the numerical references 1 through 8 are built in the heat source equipment A. Reference B designates an indoor unit, which includes a flow rate adjuster 5 (or a flow control valve 5) and a heat exchanger 6 on an application side. The heat source equipment A and the indoor unit B are separately located and connected through a first connection pipe C and a second connection pipe D, whereby a refrigeration cycle is formed.
One end of the first connection pipe C is connected to the heat exchanger 3 on the heat source equipment side through the first control valve 4 and the other end of the first connection pipe C is connected to the flow rate adjuster 5. One end of the second connection pipe D is connected to the four-way valve 2 through the second control valve 7 and the other end of the second connection pipe D is connected to the heat exchanger 6 on the application side. Further, an oil return hole 8a is provided in a lower portion of an effluent pipe having a U-like shape of the accumulator 8.
A refrigerant flow of the air conditioner will be described in reference of FIG. 11. In FIG. 11, an arrow of solid line designates a flow in cooling operation and an arrow of broken line designates a flow in heating operation.
At first, the flow in cooling operation will be described. A gas refrigerant having a high-temperature and a high-pressure, which is compressed by the compressor 1 flows through the four-way valve 2 to the heat exchanger on the heat source equipment side 3, wherein it is condensed and liquefied by exchanging heat with a heat source medium such as air and water. Thus condensed and liquefied refrigerant flows through the first control valve 4 and the first connection pipe C to a flow rate adjuster 5, wherein it is depressurized to a low pressure to be in a two-phase state of a low pressure and evaporates and vaporized by exchanging heat with a medium on the application side such as air in the heat exchanger on the application side 6. Thus evaporated and vaporized refrigerant returns to the compressor 1 through the second connection pipe D, the second control valve 7, the four-way valve 2, and the accumulator 8.
In the next, a flow in heating operation will be described. A gas refrigerant in a high-temperature and a high-pressure which is compressed by the compressor 1 flows into the heat exchanger on the application side 6 through the four-way valve 2, the second control valve 7 and the second connection pipe D and is condensed and liquefied by exchanging heat with a medium on the application side such as air in the heat exchanger 6. Thus condensed and liquefied refrigerant flows into the flow rate adjuster 5, wherein it is depressurized to a low pressure to be a two phase state of a low pressure and evaporates and vaporizes by exchanging heat with a heat source medium such as air and water in the heat exchanger on the heat source equipment side 3 after passing through the first connection pipe C and the first control valve 4. Thus evaporating and vaporizing refrigerant returns to the compressor 1 through the four-way valve 2 and the accumulator 8.
Conventionally, chloro fluoro carbon (hereinbelow referred to as CFC) or hydro chloro fluoro carbon (hereinbelow referred to as HCFC) is used as a refrigerant for such an air conditioner. However, chlorine contained in the these molecules destructs an ozone layer in the stratosphere. Therefore, CFC was already abolished and production of HCFC was already started to regulate.
Instead of these, hydro fluoro carbon (hereinbelow referred to as HFC) which does not contain chlorine in its molecules is practically used for an air conditioner. When an air conditioner using CFC or HCFC is aged, it is necessary to substitute an air conditioner using HFC because the refrigerant such as CFC and HCFC has been abolished or regulated to produce.
Because the heat source equipment A and the indoor unit B use a refrigerating machine oil, an organic material, and an heat exchanger respectively for HFC are different from those for HCFC, it is necessary to change a refrigerating machine oil, an organic material, and a heat exchanger, respectively for exclusive use of HFC. Further, because the heat source equipment A and the indoor unit B respectively for CFC or HCFC may be aged, it is necessary to exchange these and such an exchange is relatively easy.
On the other hand, because in a case that the first connection pipe C and the second connection pipe D connecting the heat source equipment A to the indoor unit B are long or are buried in a pipe shaft, above a ceiling, in a like location of a building, it is difficult to exchange for new pipes and existing pipes are ordinarily not decrepit, it is possible to simplify piping work by using the existing first connection pipe C and the existing second connection pipe D for the air conditioner using CFC or HCFC.
However, in the first connection pipe C and the second connection pipe D used for the air conditioner utilizing CFC or HCFC, a refrigerating machine oil of a mineral oil for the air conditioner utilizing CFC or HCFC and a deteriorated substance of a refrigerating machine oil retain as a sludge.
FIG. 12 shows a critical solubility curve for a exhibiting solubility of a refrigerating machine oil for HFC with a refrigerant of HFC (R407C) when a mineral oil is mixed to the refrigerant, wherein an abscissa designates a quantity of oil (WT %) and an ordinate designates a temperature (.degree. C.). When a certain quantity or more of a mineral oil is included in a refrigerating machine oil (a synthetic oil such as an ester oil or an ether oil) of an air conditioner utilizing HFC, compatibility with a HFC refrigerant is lost as shown in FIG. 12, wherein in a case that a liquid refrigerant is accumulated in a accumulator 8, the refrigerating machine oil for HFC separates and flows on the liquid refrigerant, whereby a sliding portion of compressor is seized because the refrigerating machine oil does not return from an oil return hole 8a located in a lower portion of the accumulator 8 to the compressor.
Further, when a mineral oil is mixed, the refrigerating machine oil for HFC is deteriorated. Further, when CFC or HCFC is mixed in the refrigerating machine oil for HFC, it is deteriorated by a component of chlorine contained in CFC or HCFC. Further, the refrigerating machine oil for HFC is deteriorated by a component of chlorine contained in sludge of a deteriorated substance of refrigerating machine oil for CFC or HCFC.
Therefore, a first connection pipe C and a second connection pipe D, which were used in an air conditioner utilizing CFC or HCFC, were conventionally cleaned by a flushing liquid for exclusive use, (ex. HCFC 141b or HCFC 225) in use of a flushing machine. Hereinbelow, such a method is referred to as a flushing method 1.
In the next, another method is disclosed in JP-A-7-83545. There is proposed, as shown in FIG. 13, a heat source equipment A for HFC, an indoor unit B for HFC, a first connection pipe C and a second connection pipe D are connected in step 100; HFC and a refrigerating machine oil for HFC are charged thereinto in Step 101; an air conditioner is operated for flushing in Step 102; the refrigerant and the refrigerating machine oil in the air conditioner are recovered and a new refrigerant and a new refrigerating machine oil are charged in Step 103; and flushing is repeated by a predetermined number of times by operating the air conditioner in Steps 104 and 105, wherein a flushing machine is not used. Hereinbelow, such a method is referred to as flushing method 2.
However, the conventional flushing method 1 had following problems.
In the first place, a flushing liquid to be used was HCFC, of which ozone layer destruction coefficient is not 0. Therefore, substitution of HCFC for HFC as a refrigerant of air conditioner was in contradiction to such a usage of HCFC. Particularly, HCFC141b has a large ozone destruction coefficient of 0.11, wherein a usage of HCFC141b was problematic.
In the second place, the flushing liquid to be used should have been completely safe in terms of combustibility and toxicity. HCFC141b is combustible and has low toxicity. HCFC225 is not combustible but has low toxicity.
In the third place, a boiling point of HCFC141b is so high as 32.degree. C. and that of HCFC225 is so high as 51.1 through 56.1.degree. C. When an outdoor air temperature was lower than this boiling point, especially in a winter season, the flushing liquid remained in the first connection pipe C and the second connection pipe D because the liquid was in an liquid state after flushing. Because the flushing liquid was HCFC containing an ingredient of chlorine, the refrigerating machine oil for HFC was deteriorated.
In the fourth place, the flushing liquid is necessary to be completely recovered in consideration of the environment. And, it is also required to re-flush by a high-temperature nitrogen gas or the like so as not to cause the third problem. Thus, flushing work took a labor hour.
In the conventional flushing method 2 mentioned in the above had the following problems.
In the first place, in an embodiment disclosed in JP-A-7-83545, it was necessary to repeat flushing by a HFC refrigerant by three times and the HFC refrigerant used for the steps of flushing operation included impurities. Accordingly, it was impossible to reuse the refrigerant after recovery. In other words, it was necessary to prepare a refrigerant of three times as much as the quantity of ordinarily charged refrigerant, wherein there were problems in the cost and the environment.
In the second place, the refrigerating machine oil was exchanged after the steps of flushing operation, it was necessary to prepare a refrigerating machine oil three times as much as the quantity of ordinarily charged refrigerating machine oil, wherein there were problems in the cost and the environment. Further, the refrigerating machine oil for HFC was an ester or an ether, both of which had high hygroscopicity, wherein it was necessary to control water content in a refrigerating machine oil to be exchanged. Further, because the refrigerating machine oil was filled by a human to washed the air conditioner, there was a danger that the oil was under-charged or over-charged, wherein there was a possibility that troubles would occur in succeeding operation. Such an over-charging may cause destruction of a portion for compressing and overheating of a motor by compression of oil, and such an under-charging may cause mal-lubrication.